To determine the optimal combination of enhancer and boundary elements for use in mosquito transgenesis, the following specific aims are to be completed: 1) evaluate a number of enhancer elements to determine which one causes the largest increase in transcription levels in ae. aegypti; 2) assess the ability of transcriptional activator proteins to further increase the effects of enhancer elements; 30 determine if boundary elements can protect transgenes in Ae. aegypti from position effects; 4) determine if the addition of enhancer and boundary elements can improve the levels of expression from tissue-specific promoters.